摘要:

The interaction between Junin virus (JV) and Tacaribe virus (TACV) during mixed infections of RK13 cells was examined. The effects of a prior infection with JV upon TACV replication depended on the time between the two inoculations. Simultaneous infection of RK13 cells with TACV and JV did not alter the plaquing efficiency of TACV; but if there was a 1- to 24-hour delay between JV preinfection and TACV superinfection, a variable increase of TACV replication was observed. The enhancement of TACV replication by preinfection with JV was dependent on several factors, such as the MOI of both viruses and the integrity of the JV genome. This effect was also highly specific, as the plaquing efficiencies of the arenavirus Pichinde and the unrelated vesicular stomatitis virus were not affected by preinfection with JV at any multiplicity assayed. The majority of the progeny formed in cells superinfected with TACV 1 or 24 h after JV infection was partially neutralized by antisera to both viruses. This suggested that phenotypic mixing, with JV or TACV genomes enclosed within an envelope containing TACV and JV glycoproteins, had occurred.

ISSN:0300-5526    

DOI:10.1159/000149560

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The effect of the attenuated XJC13 and XJO strains of Junin virus (JV) was studied in guinea pigs infected before and during pregnancy. The 58% mortality rate in animals infected during gestation and the 16.7% mortality rate in chronically infected animals were attributed to a viral effect. An abortion rate of 33% occurred in animals infected before the 7th week of gestation. Regardless of the time of infection, JV was isolated from central nervous system tissue, placentas, and fetuses of animals killed just before parturition, even when circulating neutralizing antibodies were present. Results confirmed that transplacental infection is a regular event and showed that guinea pigs are more susceptible to attenuated JV strains during pregnancy, most probably due to immunosuppression, hormonal changes, or both.

ISSN:0300-5526    

DOI:10.1159/000149561

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

17 adenovirus strains from various parts of the United States and Europe were characterized by immunological and biochemical methods. They were antigenically related to adenovirus 15 (Ad15) in neutralization tests. In hemagglutination-inhibition tests, a relationship was seen to Ad9, but not to Ad15. These strains were named Ad15/H9 intermediate strains. The relatedness of prototypes Ad15 and Ad29 in neutralization tests and of Ad9 and Ad8 in hemagglutination-inhibition tests was also found in the strains studied. The DNAs of these strains were analyzed by use of restriction endonucleases. After cleavage with the enzymes BamHl, Bglll, BstElI, Hindlll, and Smal, fragment patterns of Ad15/H9 strains were found to be different from the prototypes and were more closely related to Ad9 than to Ad15. Furthermore, the 17 strains could be classified into six different genome types, a-f.

ISSN:0300-5526    

DOI:10.1159/000149562

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The DNA of canine adenovirus (canAV 1, strain Behring H.c.c. 269) was characterized in detail. The molecular weight of canAV DNA was (20.1 ± 0.1) × 106 daltons as determined by contour length measurements, and 19.9 x 106 daltons as determined by restriction enzyme analysis. A terminal protein was found to be covalently linked to the 5’ ends of canAV DNA. Physical maps of viral DNA were constructed for BamHl, Clal, Sacl, Sail, and Smal enzymes. Three international strains of canAV [American Type Culture Collection (ATCC) catalogue No. VR-800, VR-293, and VR-133] were analyzed under the same conditions. CanAV 1 (ATCC VR-133 and VR-293) had DNA cleavage patterns identical to the H.c.c. 269 strain, whereas the DNA cleavage pattern of canAV 2 (ATCC VR-800) was clearly differ

ISSN:0300-5526    

DOI:10.1159/000149563

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

Rous sarcoma virus (RSV)-transformed Chinese hamster fibroblasts, containing approximately ten copies of the DNA domain comprising a single provirus and its flanking cellular sequences, were arrested in metaphase, and the chromosomes were fractionated by size in a sucrose gradient. The resolution of polymorphic ribosomal genes, the dihydrofolate reductase gene, and the c-src gene demonstrated that the gradient can distinguish between small, medium, and large chromosomes. The same DNA domain carrying the RSV provirus was found to be associated with chromosomes of all three size classes. Polymorphic copies of the domain in small and large chromosomes could be distinguished from those in medium-sized chromosomes because of the polymorphism in the Xhol and EcoRl sites on 5’ and 3’ adjacent cellular sequences, respectively. The presence of the same provirus domain on different chromosomes, together with the karyological data showing trisomies in the same chromosome size classes, suggest that the provirus domain, possibly the entire replicon, was duplicated and transferred to different nonhomologous chromosomes, and the transfer was followed by duplication of the target chromosomes. The possibility that proviral long terminal repeats might be involved in replicon transfer is discus

ISSN:0300-5526    

DOI:10.1159/000149564

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The antiherpesvirus activity of CP-20,961 [N,N-dioctadecyl-N’,N’-bis (2-hydroxyethyl) propanediamine, or Avridine] was investigated in cultured guinea pig embryo (GPE) cells. Plaque formation of herpes simplex virus type 1 (HSV1) and type 2 (HSV2) was inhibited, but vesicular stomatitis virus replication was not inhibited, in GPE cells treated with CP-20,961 before infection. The ID50 concentration of CP-20,961 for HSV was about 50 µg/ml for 3–4 days of pretreatment. After virus adsorption and penetration, the same concentration of CP-20,961 had no effect on HSV plaque formation. The compound showed no detergent-like properties nor did it elicit any detectable interferon activity. Thus, the anti-HSV activity of CP-20,961 appeared to be associated with blocking the adsorption or penetration of the virus o

ISSN:0300-5526    

DOI:10.1159/000149565

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

3 mM n-butyrate, which effectively induces synthesis of Epstein-Barr virus (EBV) antigens in the producer P3HR-1 cell line, inhibited the transformation of umbilical cord blood lymphocytes by EBV. The drug inhibited both EBNA synthesis and stimulation of host cell DNA synthesis by strain B95–8. This effect was less pronounced at lower concentrations, but even at 0.1 mM (which did not affect DNA synthesis in mitogen-stimulated lymphocytes or established lymphoblastoid cell lines) the synthesis of EBNA and stimulation of host cell DNA synthesis in EBV-infected lymphocytes were delaye

ISSN:0300-5526    

DOI:10.1159/000149566

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The combination of 12–0-tetradecanoylphorbol-13-acetate and n-butyrate induced Epstein-Barr virus (EBV)-associated alkaline DNase in Raji cells. The anti-early-antigen-positive sera neutralized EBV-associated DNase activity. The enzyme activity was eluted at about 0.20 and 0.24 M KC1 from DEAE-cellulose and phosphocellulose columns, respectively. The partially purified enzyme was sensitive to (NH4)2S04 and spermine. Immunological and biochemical properties of EBV-associated DNase induced in Raji cells were similar to those of the enzyme induced in P3HR-1 cell

ISSN:0300-5526    

DOI:10.1159/000149567

出版商:S. Karger AG    

年代:1985

数据来源: Karger